US4485399A - Method and apparatus approximately correcting errors in a digital video signal - Google Patents

Method and apparatus approximately correcting errors in a digital video signal Download PDF

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Publication number
US4485399A
US4485399A US06/357,619 US35761982A US4485399A US 4485399 A US4485399 A US 4485399A US 35761982 A US35761982 A US 35761982A US 4485399 A US4485399 A US 4485399A
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value
picture point
values
stage
zero
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US06/357,619
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English (en)
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Axel Schulz
Josef Sochor
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/85—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression
    • H04N19/89—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression involving methods or arrangements for detection of transmission errors at the decoder
    • H04N19/895—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression involving methods or arrangements for detection of transmission errors at the decoder in combination with error concealment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/64—Circuits for processing colour signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/79—Processing of colour television signals in connection with recording
    • H04N9/87—Regeneration of colour television signals
    • H04N9/88—Signal drop-out compensation
    • H04N9/888—Signal drop-out compensation for signals recorded by pulse code modulation

Definitions

  • This invention concerns a method and apparatus for covering over or making invisible errors that are detected in a digital video signal by substituting for an erroneous light value a light value obtained by averaging light values of neighboring picture points.
  • the invention is applicable with respect to color television signals that are encoded separately with respect to the color information and the luminance information, hereinafter referred to as a separately coded color television signal. Averages are made for both of the components. More particularly, shift registers are provided for storing the video signals as they come, with a one line delay and with a two line delay, in order to make possible averaging vertically and diagonally, as well as horizontally.
  • the invention has the advantages that the method is applicable without changes in principle both for processing the digital luminance components and for processing the digital color components of a separately coded color television signal. All problems regarding the time lapse within the components involved in a necessary approximation change now disappear when two neighboring points involve errors.
  • FIG. 1 is a diagram of a faulty picture point and neighboring picture points as arranged on a viewing tube;
  • FIG. 2a is a basic block diagram of circuitry utilized in the practice of the invention.
  • FIG. 2b is a block circuit diagram of a circuit in accordance with the invention utilizing the circuitry of FIG. 2a;
  • FIG. 3 is a circuit diagram constituting a detail of the block diagram of FIG. 2 for illustrating the obtaining of average values
  • FIG. 4 is a basic block diagram for obtaining the control signals for the circuit of FIG. 2.
  • the line containing the faulty picture point is designated n, the preceding one n-1 and the following one n+1.
  • a number of reference lines are drawn in FIG. 1 through the single faulty picture point which is distinguished by being a solid black point, while the undisturbed picture points are open circles.
  • the reference line A--A runs in the horizontal scanning direction, the reference line B--B perpendicularly thereto, the reference line C--C on the "bardexter" ("right”) diagonal and the reference line D--D on the "barsinister” ("left”) diagonal.
  • the picture points lying before the reference line B--B in the horizontal scanning direction, in the neighborhood of the faulty point are designated with "-", those lying after the reference line B--B in the horizontal scanning direction are designated with the symbol "+".
  • the various picture points in the neighborhood of an immediately adjoining faulty picture point are defined in their relation to the faulty picture point, in each case by two components: by their position on the line of the faulty point (n), or the preceding line (n-1), or the following line (n+1) and, in the second place, by their position immediately above or below the faulty point (reference line B--B), or ahead of it (-), or after it (+).
  • the definition of the position of a particular undisturbed picture point relative to the faulty point can also be made by means of the reference line star (A--A,B--B,C--C,D--D) in connection with the line designation (n-1,n,n+1).
  • FIG. 2a shows how substitute signals can be provided for insertion at a picture point in case the signal for that picture point is subject to an error
  • FIG. 2b shows, likewise in block diagram, a circuit for formation of a substitute signal and for its addition to the digital video signal to provide the most complete covering over of the error that is possible.
  • the addition process is simple, because the commonly used error detection substitutes a zero (full black) value for a signal found to have an error.
  • a video signal receiving on an 8-bit parallel bus in a serial data stream proceeds successively through two delay devices 10 and 11, in each of which the signal is delayed by the duration of a television line.
  • All the digital video signals present in the X plane thus belong to one picture line, the one which is designated n+1 in FIG. 1; all digital signals in the Y plane are delayed by the duration of one line, and accordingly belong to line n, and the signals present in the Z plane are delayed once more by the duration of a line, and accordingly belong to the picture line n-1.
  • planes so that it is easier to imagine eight bits proceeding from left to right aligned in the line of sight when looking at the drawing.
  • the digital signals of the X plane are supplied to a shift register 12, the three outputs of which always contain signals with a time difference between them of one picture point interval. Since the digital video signals of the X plane belong to line n+1, the signal taken from the first output of the shift register 12 represents the picture point in [(n+1)+], the signal taken from the second output of the shift register 12 represents the picture point (n+1), and the signal taken from the third output of the shift register 12 represents the picture point [(n+1)-]. In a similar manner, the digital video signals of the Y plane are supplied to a second shift register 13, from the outputs of which the picture points (n+),n,(n-) are available.
  • the digital video signals of the Z plane are supplied to a third shift register 14, and the shift registers are shift register arrays, of course (so that all eight bits of each picture point are available), at the outputs of which three succeeding picture points of the line n+1 following the current picture line are available, respectively designated [(n-1)+], n-1, [(n-1)-].
  • the signals at the outputs of the shift register devices 12,13 and 14 thus provide the current picture point n, as well as the immediately adjacent picture points of its neighborhood, including those of the preceding and of the following line shown in FIG. 1.
  • addition stages are provided, respectively corresponding to the reference lines A--A,B--B,C--C and D--D passing through the current picture point, for use when the current picture point is faulty.
  • These addition stages are correspondingly designated A,B,C and D.
  • the appropriate signals at the outputs of the shift register 12,13,14 (which have all been identified above with reference to FIG. 1) are supplied to the inputs of the addition stages A,B,C and D.
  • an addition stage A there are present at respective inputs of an addition stage A the signals of the picture points (n-) and (n+), of respective inputs of an addition stage B the signals of the picture points (n-1) and (n+1), at respective inputs of an addition stage C the signals of the picture points [(n-1)-] and [(n+1)+] and at respective inputs of an addition stage D the signals of the picture points [(n-1)+] and [(n+1 )-].
  • Each of the addition stages A,B,C and D has a division stage following it, the devisor ratio of which is variable by the factor 2 according to control.
  • Detection of faulty picture points in digital color television signals is performed in an error detector not shown here or described, but known in the art and forming no part of this invention, so that it does not need to be described here. If a picture point is recognized as faulty by the error detector, the value of the faulty picture point is set to zero by the error detector. At the same time in the illustrated example, the value zero of the digital color television signal subdivided into 2 8 value steps is produced as identification for the presence of a faulty picture point. The digital color television signal is thereby reduced by one value step. If this diminution of the value region in the digital color television signal should not be permitted, the presence of faulty picture points in the digital color television signal can also be indicated over a separate signal conductor.
  • the switchable divider 16 follows the addition stage B, the switchable divider 17 the addition stage C, and the switchable divider 18 the addition stage D.
  • the outputs of every two divider circuits 15 and 16, 17 and 18, are supplied to a further addition stage, and the signals of the divider stages 15 and 16 thus go to the addition stage 19, those of the addition stages 17 and 18 to the addition stage 20.
  • the incoming digital signals are added once more, and when two usable signals are provided, at the output of the addition stage 20, the signal is reduced by half by the switchable divider 22.
  • the corresponding dividing stage 21 or 22 is switched to the ratio 1, so that the output of these dividers corresponds to the output signal of one of the divider stages 15,16,17 or 18.
  • the outputs of the two divider stages 21 and 22 are again connected to the inputs of an addition stage, the addition stage 23 in this case, which again provides its output to a divider stage 24 with a switchable division ratio.
  • a multiplexer 25 follows the division stage 24 and has one input connected to the output of the division stage 24 and its other input is provided with a digital signal that corresponds to the gray value.
  • the value "gray" can be put in as a substitution value.
  • a connection leads from the outout of the multiplexer 25 to an input of another multiplexer 26, of which the other input contains a signal of the picture point (n-1)-. By the end of the time allowed for computation, a desired undisturbed picture point signal will have reached the (n-1)- output.
  • the multiplexer 26 switches over between its two inputs for either concealing a faulty pictuure point or passing the video signal with undisturbed picture points. In this way, the resolution losses connected with the formation of average values are mitigated or suppressed.
  • the digital video signal in which its errors have been concealed is made available for use.
  • FIG. 3 shows a signal processing stage composed of an adder and a following divider corresponding to the description of FIG. 2b.
  • the addition stage A in combination with the divider 15 are shown.
  • the input signals are supplied to the adder A serially in 8-bit parallel form. These are added in accordance to their values and transmitted to the divider 15.
  • switches 31 are controlled so that either a left or right shift takes place in the bit stream and a corresponding change of the division ratio from 1 to 2 or vice versa is produced.
  • the gates 42-44 have a kind of AND function (namely output 1 when all inputs are 0); that provides a signal only when the presence of a faulty picture point is recognized.
  • the time coordination follows a quasi 2-dimensional arrangement with the serial-parallel converters 45-47 which permits determination whether around a faulty picture point of which, if any, of the neighboring picture points are likewise faulty.
  • the program content in the ROM 41 is then provided in such a way that the conditions described above are maintained with respect to the computation of substitution values with reference to the situation in the neighborhood of a faulty picture point.
  • the control of the dividers and multiplexers is produced as shown in FIG. 4 in accordance with conditions defined in a store (ROM 41).
  • ROM 41 a store
  • the signals of the X, Y and Z planes produce sequential signals at the gate 42, 43 and 44 outputs, as just described, which are then brought into 3-bit parallel form by the serial-parallel converters 45, 46 and 47 respectively serving the gates 42, 43 and 44. All nine bits are then supplied to a read-only memory 41.
  • the signals at the outputs I to VII are supplied for the control of the divider stages 15, 16, 17, 18, 21, 22 and 24, and the signals at the outputs VIII and IX are provided for the control of the multiplexers 25 and 26.
  • FIG. 2b In the block circuit diagram of FIG. 2b, one channel for one of the components of a separately coded color television signal is represented. Each of the components of the color television signal requires a channel similarly constituted in accordance with the process of the present invention.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Color Television Systems (AREA)
  • Processing Of Color Television Signals (AREA)
  • Image Processing (AREA)
US06/357,619 1981-04-09 1982-03-12 Method and apparatus approximately correcting errors in a digital video signal Expired - Fee Related US4485399A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3114275 1981-04-09
DE19813114275 DE3114275A1 (de) 1981-04-09 1981-04-09 Verfahren und schaltungsanordnung zum verdecken von fehlern in einem digitalen videosignal

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JP (1) JPS57178489A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE3114275A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4586082A (en) * 1982-05-26 1986-04-29 Sony Corporation Error concealment in digital television signals
US4605966A (en) * 1982-05-14 1986-08-12 Sony Corporation Error concealment in digital television signals
US4682230A (en) * 1986-03-21 1987-07-21 Rca Corporation Adaptive median filter system
DE3608917A1 (de) * 1986-03-18 1987-09-24 Thomson Brandt Gmbh Verfahren zur korrektur
US4736439A (en) * 1985-05-24 1988-04-05 The United States Of America As Represented By The Secretary Of The Navy Image preprocessing by modified median filter
US4748499A (en) * 1985-09-03 1988-05-31 Victor Company Of Japan, Ltd. Demultiplexing and noise reduction circuit for time division multiplexed signal
US4750037A (en) * 1985-10-07 1988-06-07 Victor Company Of Japan, Ltd. Noise reduction system for video signal
US4760470A (en) * 1985-09-27 1988-07-26 Ampex Corporation Multi-standard adaptive dropout compensator
US4782389A (en) * 1987-04-30 1988-11-01 Rca Licensing Corporation Adaptive M-tile sample producer
DE3809688A1 (de) * 1988-03-23 1989-10-12 Broadcast Television Syst Verfahren zur einstellung der spurlage bei einem magnetbandgeraet
US5309252A (en) * 1990-11-09 1994-05-03 Matsushita Electric Industrial Co., Ltd. Document generator including a pickup means for detecting picture information and code information
US5311314A (en) * 1989-06-20 1994-05-10 U.S. Philips Corporation Method of and arrangement for suppressing noise in a digital signal
US5424783A (en) * 1993-02-10 1995-06-13 Wong; Yiu-Fai Clustering filter method for noise filtering, scale-space filtering and image processing
US5452109A (en) * 1994-08-31 1995-09-19 Eastman Kodak Company Digital image signal processing apparatus and method for accumulating blocks of signal data from an imager
US5631979A (en) * 1992-10-26 1997-05-20 Eastman Kodak Company Pixel value estimation technique using non-linear prediction
US6028628A (en) * 1993-07-23 2000-02-22 U.S. Philips Corporation Signal correction circuit
US8072539B1 (en) 1993-07-26 2011-12-06 Cooper J Carl Apparatus and method for digital processing of analog television signals

Families Citing this family (11)

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Publication number Priority date Publication date Assignee Title
DE3121599C2 (de) * 1981-05-30 1986-11-27 Robert Bosch Gmbh, 7000 Stuttgart Verfahren und Schaltungsanordnung zum Verdecken von Fehlern in einem digitalen Videosignal
DE3311911A1 (de) * 1983-03-31 1984-10-04 Siemens AG, 1000 Berlin und 8000 München Verfahren und schaltungsanordnung zur bildfehlerkorrektur
DE3334934A1 (de) * 1983-09-27 1985-04-11 Siemens AG, 1000 Berlin und 8000 München Verfahren zur verbesserung der bildqualitaet bei gestoerter uebertragung von digitalen fernsehsignalen durch bildfehlerverdeckung
DE3400919A1 (de) * 1984-01-12 1985-09-19 Siemens AG, 1000 Berlin und 8000 München Verfahren zur feststellung der genauen fehlerbuendellaenge
DE3400908A1 (de) * 1984-01-12 1985-09-26 Siemens AG, 1000 Berlin und 8000 München Verfahren zur feststellung der fehlerbuendellaenge
GB2160065B (en) * 1984-06-09 1988-11-09 Fuji Photo Film Co Ltd Method of processing an image signal
DE3509622A1 (de) * 1985-03-16 1986-09-18 Robert Bosch Gmbh, 7000 Stuttgart Verfahren zur speicherung getrennt codierter digitaler farbvideosignale auf magnetband
DE3538735A1 (de) * 1985-10-31 1987-05-07 Bosch Gmbh Robert Verfahren und schaltungsanordnung zum verdecken von fehlern in einem digitalen videosignal
TW247984B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) * 1990-12-21 1995-05-21 Ampex
DE4211955A1 (de) * 1992-04-09 1993-10-14 Thomson Brandt Gmbh Verfahren und Vorrichtung für eine interlace-progressiv-Wandlung
DE19846453C2 (de) * 1998-10-08 2001-12-20 Infineon Technologies Ag Verfahren zur Unterdrückung des Rauschens in Signalen

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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4605966A (en) * 1982-05-14 1986-08-12 Sony Corporation Error concealment in digital television signals
US4586082A (en) * 1982-05-26 1986-04-29 Sony Corporation Error concealment in digital television signals
US4736439A (en) * 1985-05-24 1988-04-05 The United States Of America As Represented By The Secretary Of The Navy Image preprocessing by modified median filter
US4748499A (en) * 1985-09-03 1988-05-31 Victor Company Of Japan, Ltd. Demultiplexing and noise reduction circuit for time division multiplexed signal
US4760470A (en) * 1985-09-27 1988-07-26 Ampex Corporation Multi-standard adaptive dropout compensator
US4750037A (en) * 1985-10-07 1988-06-07 Victor Company Of Japan, Ltd. Noise reduction system for video signal
DE3608917A1 (de) * 1986-03-18 1987-09-24 Thomson Brandt Gmbh Verfahren zur korrektur
US4682230A (en) * 1986-03-21 1987-07-21 Rca Corporation Adaptive median filter system
US4782389A (en) * 1987-04-30 1988-11-01 Rca Licensing Corporation Adaptive M-tile sample producer
DE3809688A1 (de) * 1988-03-23 1989-10-12 Broadcast Television Syst Verfahren zur einstellung der spurlage bei einem magnetbandgeraet
US5038229A (en) * 1988-03-23 1991-08-06 Bts Broadcast Television Systems Gmbh Method of performing a tracking adjustment of a digital video recording and reproducing equipment
US5311314A (en) * 1989-06-20 1994-05-10 U.S. Philips Corporation Method of and arrangement for suppressing noise in a digital signal
US5309252A (en) * 1990-11-09 1994-05-03 Matsushita Electric Industrial Co., Ltd. Document generator including a pickup means for detecting picture information and code information
US5631979A (en) * 1992-10-26 1997-05-20 Eastman Kodak Company Pixel value estimation technique using non-linear prediction
US5424783A (en) * 1993-02-10 1995-06-13 Wong; Yiu-Fai Clustering filter method for noise filtering, scale-space filtering and image processing
US6028628A (en) * 1993-07-23 2000-02-22 U.S. Philips Corporation Signal correction circuit
US8072539B1 (en) 1993-07-26 2011-12-06 Cooper J Carl Apparatus and method for digital processing of analog television signals
US5452109A (en) * 1994-08-31 1995-09-19 Eastman Kodak Company Digital image signal processing apparatus and method for accumulating blocks of signal data from an imager

Also Published As

Publication number Publication date
DE3114275A1 (de) 1982-11-04
DE3114275C2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1989-07-06
JPS57178489A (en) 1982-11-02

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